Controlled bulk polymerization of l-lactide and lactones by dual activation with organo-catalytic systems

Kadota, Joji; Pavlović, Dražen; Honda, Hiroshi; Okada, Akinori; Agari, Yasuyuki; Bibal, Brigitte; Deffieux, Alain; Peruch, Frédéric

doi:10.1039/c4ra01239a

Cited by 42 publications

(36 citation statements)

References 77 publications

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“…[7] Therefore, the stereo-regulated ROP of rac-LA has always been at opic of interesti nt he field of polymer chemistry.I nr ecent years, the catalytic ROP of cyclic esters such as lactides (LAs) and lactones has been frequently exploredb yu sing organocatalysts, [8] as wella sd iscrete metal precursors such as complexes of tin, [9] aluminum, [10] zinc, [11] magnesium, [12] iron, [13] titanium, [14] indium, [15] yttrium, [16] rareearth metals, [17] and organo-initiators. [18] The main challenge in choosingacatalysti si dentifying one that can produce high rates of polymerization with excellent stereoregularity,i deally withoutt he need for expensive chiral auxiliaries or ligands. [19] Several highly active achiral catalysts are capableo fp roducing amorphous, heterotactic PLAs of low polydispersity values from rac-LA.…”

Section: Introductionmentioning

confidence: 99%

Highly Active and Iso‐Selective Catalysts for the Ring‐Opening Polymerization of Cyclic Esters using Group 2 Metal Initiators

Bhattacharjee

Harinath

Nayek

et al. 2017

Chemistry A European J

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A series of alkali and alkaline earth (Ae) metal complexes bearing 1,2-phenylene(bis-diphenylphosphinothioic/selenoic amine) [{Ph P(E)NH} C H ] (E=S (1-H2); Se (2-H2) ligands are reported. Alkali metal complexes [{Ph P(S)N} C H ]Na(THF) (3 a) [{Ph P(Se)N} C H ]Na(THF) (3 b), and [{Ph P(Se)N} C H ]K(THF) (4 b) were obtained in good yield by treating protic ligands 1-H2 or 2-H2 with metal hexamethyldisilazides [MN(SiMe ) ] (M=Na or K) at ambient temperature. The Ae metal complexes formulated as [{Ph P(E)N} C H ]M(THF) [E=S, M=Ca (5 a), Sr (6 a), Ba (7 a); E=Se, M=Ca (5 b), Sr (6 b), Ba (7 b)] can be synthesized by using two routes. The molecular structures of the free ligand 1-H2 and metal complexes 5 a,b-7 a,b in their solid states were established. Complexes 3 a and 3 b are isostructural; however, in complex 4 b, an attachment different from ligand 2 was observed. The complexes 5 a,b-7 a,b are isostructural and each metal ion exhibits a distorted pentagonal bipyramidal geometry around it. All Ae metal complexes 5 a,b-7 a,b were tested for the ring-opening polymerization (ROP) of racemic lactide (rac-LA) and ϵ-caprolactone (ϵ-CL) at room temperature. Calcium complexes 5 a and 5 b show excellent iso-selectivity, with P values of 0.78-0.87 at 298 K and with a high degree of polymerization control, whereas the corresponding strontium complexes 6 a and 6 b exhibit moderate iso-selectivity, and barium complexes 7 a and 7 b yield only atactic polylactides (PLAs). In all cases, the catalyst initiates the ROP catalytic cycle in the absence of any external initiator. Kinetic studies of the polymerization reactions indicate the relative order of polymerization rate increases with increase in the size of the metal ion: Ba>Sr>Ca.

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Section: Introductionmentioning

confidence: 99%

Highly Active and Iso‐Selective Catalysts for the Ring‐Opening Polymerization of Cyclic Esters using Group 2 Metal Initiators

Bhattacharjee

Harinath

Nayek

et al. 2017

Chemistry A European J

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“…Although there are some reports about the bulk ROP of cyclic esters using organocatalysts, the advantages of bulk conditions have not been investigated in detail. [12][13][14]25,26,37,[60][61][62][63][64][65][66][67][68][69][70][71][72][73] We now describe the organophosphate-catalyzed bulk ROP of various cyclic esters, such as ε-CL,…”

Section: Introductionmentioning

confidence: 99%

“…7,[20][21][22][23][24]26 In addition, the bifunctional catalytic system possessing two activation sites for the monomer and propagating chain end also turned out to be effective for the ROP of ε-caprolactone (ε-CL) and LA. [27][28][29][30][31][32][33][34][35][36][37] For example, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as a bifunctional catalytic system promotes the ROP of the ε-CL, whereas DBU is ineffective, 20 and the MSA/DMAP bifunctional 4 catalytic system promotes the ROP of the LA, whereas MSA alone does not work. 31 Despite such numerous efforts, there are still many problems to be overcome for the industrial scale production of aliphatic polyesters using an organocatalytic system.…”

Section: Introductionmentioning

confidence: 99%

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

et al. 2015

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Abstract. The ring-opening polymerizations (ROPs) of ε-caprolactone (ε-CL), -varelolactone, 1,5-dioxepan-2-one, trimethylene carbonate, and L-lactide were performed in the bulk using an organophosphate, such as diphenyl phosphate, bis(4-nitrophenyl)phosphate, and di(2,6-xylyl)phosphate, as the catalyst. The ROPs proceeded in a well-controlled manner even in the bulk condition to afford well-defined aliphatic polyesters, polyester-ether, and polycarbonate with relatively low dispersities. Notably, the amount of the loaded catalyst was successfully reduced when compared to the conventional organophosphate-catalyzed ROP in solution. A kinetic study revealed the controlled/living nature of the present bulk ROP system, which allowed us to produce the block copolymers composed of polyesters, polyester-ether, and polycarbonate in one-pot. Syntheses of the end-functionalized poly(ε-caprolactone)s (PCLs) and poly(trimethylene carbonate) were successfully demonstrated using alcohol initiators possessing highly reactive functional groups. Furthermore, the α,ω-dihydroxy telechelic PCL-diol as well as the three-and four-armed star-shaped PCL-polyols were also easily obtained by using the polyols as an initiator. Finally, the one-pot synthesis of polyurethane via the ROP of ε-CL and subsequent urethane forming reaction was demonstrated by taking advantage of the dual catalytic abilities of the organophosphate for both the ROP and polyurethane synthesis.

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“…The stereo-composition of the polymers affects the physical and chemical properties of themselves. Usually, PLA is prepared by the ring-opening polymerization (ROP) of lactide initiated by metal complexes, such as some alkoxides of Sn [7], Al [8][9][10][11][12], Zn [13][14][15][16], Mg [17][18][19], Fe [20], Ti [21][22][23][24][25][26], In [27], rare earth metal [28][29][30][31][32][33], organo-catalytic system [34,35], and enzyme [36]. In addition, the ring-opening copolymerization of epoxides and cyclic anhydrides has also the potential to produce a wider variety of polymer backbone structures [37,38].…”

Section: Introductionmentioning

confidence: 99%

Effect of the phenyl ring substituent on stereoselectivity in the ring-opening polymerization of the rac-lactide initiated by salen aluminum complexes

Wen

et al. 2015

Colloid Polym Sci

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A number of unreported salen aluminum complexes bearing Schiff base ligands starting from (R,R)-1,2-diammoniumcyclohexane mono-(+)-tartrate salt were synthesized. These complexes were characterized by 1 H, 13 C NMR, and elemental analysis. These complexes were employed as initiators for the ring-opening polymerization (ROP) of Llactide and rac-lactide. Complex 3 (R = Br) showed the highest activity for the ROP of L-lactide among these complexes, and complex 2 (R = i Pr) possessed the highest stereoselectivity for the ROP of rac-lactide among these aluminum isopropoxides. The kinetics studies of the polymerization employed complex 2 as initiator indicated that the polymerization rate was first-ordered in lactide and initiator.

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Controlled bulk polymerization of l-lactide and lactones by dual activation with organo-catalytic systems

Cited by 42 publications

References 77 publications

Highly Active and Iso‐Selective Catalysts for the Ring‐Opening Polymerization of Cyclic Esters using Group 2 Metal Initiators

Highly Active and Iso‐Selective Catalysts for the Ring‐Opening Polymerization of Cyclic Esters using Group 2 Metal Initiators

Organophosphate-catalyzed bulk ring-opening polymerization as an environmentally benign route leading to block copolyesters, end-functionalized polyesters, and polyester-based polyurethane

Effect of the phenyl ring substituent on stereoselectivity in the ring-opening polymerization of the rac-lactide initiated by salen aluminum complexes

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